How Gamma Knife Works
The Leksell Gamma Knife® Perfexion™ utilizes the latest advanced diagnostic imaging and three-dimensional treatment planning software to deliver 192 finely-focused beams of gamma radiation to small targets inside the brain.
The beams converge at a point to treat the affected tissue, while minimizing the damage of healthy brain tissue.
What happens during Gamma Knife treatment?
Once a patient’s condition is reviewed by our multidisciplinary team and Gamma Knife treatment is deemed appropriate, the patient will be scheduled for a treatment day. On the day of treatment, there are several steps that take place.
- First, a lightweight frame is attached to the patient’s head. Local anesthesia is used before the frame is secured.
- Second, the patient has an MRI imaging study or, in the case of an arteriovenous malformation, an angiography may be needed in order to precisely locate the diseases area. Data from the imaging study is transferred into the treatment planning computer.
- Next, while the patient rests, the treatment team (a neurosurgeon, radiation oncologist and physicist) uses advanced software to determine the treatment plan. This takes one or two hours to complete, depending on the complexity and location of the disease.
- When the individual treatment plan is completed, the patient is placed on the Gamma Knife couch and precisely positioned. The patient is then moved automatically, head first into the machine, and treatment begins.
Treatment typically lasts from 15 minutes to an hour or more, during which time the patient feels nothing unusual. Actual treatment time varies based on the condition being treated and its location. - Following treatment, the patient is automatically moved out of the machine, and the head frame is removed. Gamma Knife treatment is usually an outpatient procedure, but some cases may require an overnight stay. If a patient is treated on an outpatient basis, he or she will be observed for a period of time and released. If the procedure has been designated as inpatient, then the patient will be admitted to the hospital.
The effects of Gamma Knife radiosurgery occur over several days to several years, depending on the type of medical condition treated. The radiation alters the DNA of the tumor or lesion being treated so that the cells no longer reproduce, eventually rendering the lesion static. Some abnormalities dissolve gradually, eventually disappearing. Others simply exhibit no further growth. The effectiveness of the treatment is monitored by MRI scans at regular intervals. The goal of radiosurgery is tumor control, which is defined as stable tumor size or tumor shrinkage. For vascular malformations, control is generally considered total obliteration.
